http://en.wikipedia.org/wiki/Elisabeth_SladenElisabeth Sladen played the popular companion Sarah Jane Smith. She passed away on 19th April of this year after a long battle with cancer. Her death has saddened many Whovians. She featured alongside Jon Pertwee (3rd Doctor), Tom Baker (4th Doctor), David Tennant (10th Doctor) and Matt Smith (11th Doctor-Even though she never featured in a Who episode. He was in the Sarah Jane Adventures episode The Death of The Doctor). She is probably the most popular assistant.feel free to add your tributes here